<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
		
	</head>
	<body>
		<table>
			  <tr>
				 <td><img src="" /></td>
				 <td colSpan="3">购物简易计算器</td>
			  </tr>
			  <tr>
				 <td>第一个数</td>
				 <td colSpan="3">
					 <input type="text" id="num1" />
				 </td>
			  </tr>
			  <tr>
				 <td>第二个数</td>
				 <td colSpan="3">
					 <input type="text" id="num2" />
				 </td>
			  </tr>
			  <tr>
				 <td>
					<!-- <input type="button" value=" + " onclick="add()"/> -->
					<input type="button" value=" + " onclick="cal('+')"/>
				 </td>
				 <td>
					 <!-- <input type="button" value=" - " onclick="sub()"/> -->
					 <input type="button" value=" - " onclick="cal('-')"/>
				 </td>
				 <td>
					 <!-- <input type="button" value=" * " onclick="mul()"/> -->
					 <input type="button" value=" * " onclick="cal('*')"/>
				 </td>
				 <td>
					 <!-- <input type="button" value=" / " onclick="div()"/> -->
					 <input type="button" value=" / " onclick="cal('/')"/>
				 </td>
			  </tr>
			  <tr>
				 <td>计算结果</td>
				 <td colSpan="3">
					 <input  type="text" id="resultId" />
				 </td>
			  </tr>
		  </table>
		  
		  
		  <script type="text/javascript">
			  function cal(type) {
			  	var num1 = document.getElementById('num1').value;
			  	var num2 = document.getElementById('num2').value;
				var result;// undefined
				switch(type) {
					case '+':
						result = parseInt(num1) + parseInt(num2);
					break;
					case '-':
						result = parseInt(num1) - parseInt(num2);
					break;
					case '*':
						result = parseInt(num1) * parseInt(num2);
					break;
					case '/':
						result = parseInt(num1) / parseInt(num2);
					break;
				}
			  	var resultInputObj = document.getElementById('resultId');
			  	resultInputObj.value = result;
			  }
			  
		  	function add() {
				var num1 = document.getElementById('num1').value;
				var num2 = document.getElementById('num2').value;
				var result = parseInt(num1) + parseInt(num2);
				var resultInputObj = document.getElementById('resultId');
				resultInputObj.value = result;
			}
			
			function sub() {
				var num1 = document.getElementById('num1').value;
				var num2 = document.getElementById('num2').value;
				var result = parseInt(num1) - parseInt(num2);
				var resultInputObj = document.getElementById('resultId');
				resultInputObj.value = result;
			}
			
			function mul() {
				var num1 = document.getElementById('num1').value;
				var num2 = document.getElementById('num2').value;
				var result = parseInt(num1) * parseInt(num2);
				var resultInputObj = document.getElementById('resultId');
				resultInputObj.value = result;
			}
			
			function div() {
				var num1 = document.getElementById('num1').value;
				var num2 = document.getElementById('num2').value;
				var result = parseInt(num1) / parseInt(num2);
				var resultInputObj = document.getElementById('resultId');
				resultInputObj.value = result;
			}
		  </script>
	</body>
</html>
